Nonhuman adenoviral vectors for gene therapy

描述（由申请人提供）： 尽管人腺病毒（HAd）载体作为用于多种基因治疗和疫苗应用的递送系统具有许多优点，但载体免疫性是与这些载体相关的主要缺点之一。这是由于在大多数人群中存在预先存在的HAd特异性免疫力，以及首次接种后出现载体特异性免疫应答。HAd特异性免疫显著降低HAd载体摄取的效率后，再施用相同的载体，从而大大降低了转基因表达的水平和持续时间。与HAd载体相关的另一个主要问题是由先天免疫激活引起的急性炎症反应和肝毒性。我们的假设是HAd5、牛腺病毒3型（BAd3）和猪腺病毒3型（PAd3）的主要受体是不同的，因此，由这些腺病毒载体转导的细胞类型的库将是不同的。该提议解决了通过依次施用人和非人腺病毒载体来逃避载体免疫的核心问题。这将避免毒性并允许减少每次接种的载体剂量而不损害治疗效果。在特定目标1下，将评价非人腺病毒载体用于基因治疗的功效。特别地，将确定转导效率、载体的水平和持久性以及载体基因的表达。具体目标2阐述了已知的腺病毒受体和共受体在非人腺病毒载体内化中的作用。随后，将进行一系列体内实验，以评价人和非人腺病毒载体的顺序施用在规避载体特异性免疫应答和毒性中的有用性（特异性目的3）。这些体内实验将在正常免疫活性小鼠和主要组织相容性复合物（MHC）I类缺陷小鼠中进行，以确定细胞毒性T细胞在限制载体转导、持久性和生物分布中的作用。将在乳腺癌小鼠模型中进行其他实验，以确定静脉内接种与瘤内接种后是否发生基因表达和毒性差异。该项目的成功完成将为基因治疗应用提供一种有效的规避腺病毒载体免疫和毒性的策略。

DESCRIPTION (provided by applicant): In spite of a number of advantages of human adenovirus (HAd) vectors as a delivery system for a variety of gene therapy and vaccine applications, the vector immunity is one of the major disadvantages associated with these vectors. This is due to the presence of preexisting HAd-specific immunity in the majority of the human population and the development of a vector-specific immune response following the first inoculation. HAd-specific immunity significantly lowers the efficiency of HAd vector uptake following readministration of the same vector and thus drastically reduces the levels and duration of transgene expression. Another major concern associated with HAd vectors is an acute inflammatory response and hepatotoxicity caused by activation of innate immunity. Our hypothesis is that the primary receptors for HAd5, bovine adenovirus type 3 (BAd3) and porcine adenovirus type 3 (PAd3) are distinct, and therefore, the repertoire of cell types transduced by these adenoviral vectors will be different. This proposal addresses the core issue of eluding vector immunity by sequential administration of human and nonhuman adenoviral vectors. This will avoid toxicity and allow a reduction of the vector dose per inoculation without compromising the therapeutic effect. Under Specific Aim 1, the efficacy of nonhuman adenoviral vectors for gene therapy will be evaluated. In particular, transduction efficiency, the level and persistence of the vector and expression of the vector gene/s will be determined. Specific Aim 2 addresses the role of known adenoviral receptors and co-receptors in internalization of nonhuman adenoviral vectors. Subsequently, a series of in vivo experiments will be conducted to evaluate the usefulness of sequential administration of human and nonhuman adenoviral vectors in circumventing the vector-specific immune response and toxicity (Specific Aim 3). These in vivo experiments will be done in normal immunocompetent mice and major histocompatibility complex (MHC) class I-deficient mice to determine the role of cytotoxic T cells in limiting vector transduction, persistence and biodistribution. Additional experiments will be carried out in a mouse model of breast cancer to determine if differences in gene expression and toxicity occur following intravenous vs. intratumoral inoculation. The successful completion of this project should provide an effective strategy for circumvention of adenoviral vector immunity and toxicity for gene therapy applications.